Broadcasting system



. March 9 1926. 1,576,309

E. E. CLEMENT v BRADCASTINGSYSTEM i Filed Oct. s, 192s V 5 sheets-sheet. 1

March 9 1926.

E. E. CLEMENE BROADCASTING SYSTEM March 9 ,l 1926. y E. E. CLEMENT BRoADcAsTNG SYSTEM Filed Oct. 6, 1923 3 SheetS-Shee 5 ww LHHT w N RNW QN n mvmv L M u mwa l I m5 sk@ Vu. wm g mm. Si NNN m; N j @JINN NN NML MN un, r h am HIFI JN @N m W1 NNW .I `m\ um Ma Min Mu ww @n INN mlww Patented Mar. 9, 1926.

UNITED srATes rn'ruurv r were rics

-EDWARD E. CLEMENT, F WASHINGTON, DISTRICT 0F COLUMBIA, ASSIGNOR 'I'O ED- WARD F. COLLADAY, WASHINGTON, DISTRICT OF COLUMBIA.

BROADCASTING sYsrnM. l

Application filed October 6, 1923. Serial No. 667,024.

To all whom t may concern.'

Be it known that I, EDWARD E. CLEMENT, a citizen of the United States, residinor at Washington, in the District of Columoia, vhave invented certain new and useful Im- -provements in Broadcasting Systems, of

which the following is a specification, refer ence being had therein to the accompanying drawing.

My invention relates to broadcasting systems. For Va completely organized system of this kind there are a number of essentials to be considered which hav-e not yet been renfclered available in pure lradio transmission to my knowledge. Among these are, secrecy .or restriction of the service to those alone who pay for it; uniformity and continuityv of service equal at least to those possible in standard wired systems; ethciencyin transmission and fidelity in reproduction; tests ing, control, metering and supervision of the service from a central point. It will be observed that these requisites of goed servlce ca ll for means of bothdistributive and se l'.lective character, that is to say, means for distributing' the broadcast program or coinmunications to .all consumers in common, and means for individualizing each consumer for any purpose when necessary. vIt is the object of my invention to supply these meansy by superposing an organized broadcasting s stem as a phantom upon a combination o existing wired systems, and without interfering with the ordinary functions of said Wired systems, to utilize their characteristic forms and arrangement for the appropriate guidance, distribution and con trol of modulated high frequency or carrier current waves as Well as direct and alternating current supply, and the like. Such wired systems are already divided by the nature of their respective services into two general classes, distributive systems, including electric light, power and telegraph circuits and.

p i. e., to the electric light or equivalent net- .work on one side and to the telephone line Y-wires ouv the other. By this ineens all the receiving or subscribers stations are accessible in common for broadcasting over the common or distributive medium, and each station is also accessible individually over the telephone circuit allotted to it, or to which it is allotted. In building up a complete system so as to organize on an interstate or national scale, this arrangement contemplates regional distribution, i. e., distribution in territorial districts local in character, such as a city or a county, and relaying from the national or inter-national sending stations through the regional or district centers to the local subscribers. The general broadcasting may be by any known or suitable means either pure radio or combinations of wire and radio transmission, to which broadly I lay no claim herein. In the present case for simplicity I assume pure radio for all primary station broadcasting, the principal usefulness of my combination of wire systems'being inthe final distribution 'to subscriber-consumers.

My invention is illustrated as to one form in the accompanying drawings, in which:

Fig, l is a schematic diagram indicating the layout of a general system having high power primary broadcasting stations and relayed local or regional distribution Figs. 2 and 21 taken together show some detail of the circuits and connections in the local or regional distribution area, also a metallic circuit metering scheme.

Referring to Fig. 1, l, 2 and 3 represent telephone subscribers stations, connected by wires 4, 5 and 6 to the central telephone exchange Cfand all assumed to be supplied with electric light current over a common wire network indicated at 200, from a central station 7. Superposed upon these two wire systems is a. broadcast distribution sys-l tem having a central station R fully cquipped with switchboards and a line radio or Squier transmitter for broadcastingover the wire network 200, with which it is conlnected as indicated at 208. This station R is also equipped with receiving and relayin apparatus for different wave lengths, anc has access to all lines in the telephone system through the exchange 7, as indicated by trunk wires 15. Associated with the tele'- pione subscribers stations l, 2, and 3, are broadcast receivers l, 211 and 3a, each physically connected on one side by Wires 1, 2", or 3 to the electric light circuit 200, and on metered over the individual telephone lines s 5 and 6. instruments 1, 2?) and 3 are standardized and adjusted to' one -wav'e length, so that little or no local tuning is required, all tuning being done at` thehcentrai station 8, the operator there being able ing instruments over'the telephone wires, and to determine thereby the correct ad justinent ot transmitted wave length.

ln addition to relaying messages received.

by radio waves 'from primary stations, the4 central station 8 is equipped with local modulating and Squier transmitting apparatus, for originating programs and distrib'- luting the saine over the network 200; and in no claim to this use oit`long distance telephone wires per se, but consider the use of the saine in combination with the network 200 and the local individual telephone wires as l, 5 and 6, to be within the scope of my invention, as creating an alternative all wire system which can be depended upon for maintaining continuity of important service when static or other conditions make the receipt of radiated waves roin priinary stations uncertain.

Referring to Figs. 2 and2a, I have therein shown circuits of the central oiice and suhstation equipments and connections, Fig. 2 representing the telephone sideofthe systeni, and Fig. 2 the broadcasting side of the system. Before proceeding to detail description it may be noted that iiiaccoidance with standard telephone practice, pro vision is made for keeping the telephone lines and cential oiiice circuits clear of all grounds or other disturbing connections terence -up the out oli' relay at the telephone switchboard, this however being subject to the condition that a special tone test may beput on, so that all operators may know that the line is held on the broadcast board, and subject to interruption for telephone connection. l prefer to nsethis tone test only with the broadcast operators testing plug, because his regular connecting plug includes Within its functions that of connecting a subscriber through the station' amplifier to the broadcasting transmitting set, and a connection of this character should not be interrupted without permission.

Referring articularly to the diagram, Fig. 2, A an A are two subscribers sta- ,tions connected by line wires 16-17 and to listen in on the local subscribers receiv- 18-19, respectively, to the central station C where they terminate on jacks J and J. P-P are plugs forming the terminals ol' a `cord circuit 20-21, 22-23, having i bridged repeating coil l2, ringing and listening keys ic and is', supervisory signals s-s andbridging connection to the main bat tery B. The saine battery is shown sup- Vplying current to the line relays L, L; and

through contacts of the cut oil relays L2, L?

t0 the respective lines for calling purposes. In this system, when a subscriber takes down his receiver, the line relay lights its lainp, which is extinguished when the operator inserts the answering plug.

The circuit of the line relay, relay L,.1nay be traced roni battery B through the lefthand Winding of L, leftliand contact of L8, sleeve line 19, wires lill-19, through L4 (Fig. 2a),lsubscribei"s telephone set, line 18, right hand contact of relay L3, right hand winding of L back to grounded side of battery B. Battery supply for the connected lines is thereafter taken through the cord circuit .20-2Q, 21-23, in a inanner well understood in the art. lVhen the substation telephones are out of service, with their receivers hanging on their hooks. the line'circnits are conductively open for direct current, leaving the fingers Q and Q in circuit for alternating ringing current passing through the condensers g-gi Referring now to Fig. 2, it will be observed that the broadcast. switchboard which l have designated generally by the letter R,

is connected to the subscribers7 lines by inul-v 'tiple taps marked 1G?, 17, and 17h, and 183,

19a, 19. These terminate on multiple jgichs y J2, J3, corresponding to the niultiple, jacks on the telephoneswitchboard. ltshould be noted that throughout this system the tip wires 1G and 18 with their branches are connectcd to ground, while the slccre'wiies 17 and 19 and their branches, are connected lo battery. rl`his is extended into the broadcast side of the system for the purpose ot Securing proper balance between the main battery or power plant et that side aud for example,

iis

18e, 19, and 19". l(The receiver is shown only at one substation-for sake of simplicity of illustration.) The two branches 19C' and 19d are taken from the sleeve or battery side ,ofthe line 19,'and are connected to opposite terminals of the winding of` a relay L4, which constitutes the substation cut od relay for the broadcast receiver. The Iwinding of this relay is bridged by a condenser g2 through which both ringing and voice currents can pass withoutl substantial impedance. Where the broadcast receiver is attached to a, party line substation, this relay L4 may be omitted, since on such party lines there are usually ,grounds on one side or the other.

Normally, that is to say when the tele- A phone circuit is not in use, the cut oli' relay L4 is deenergized and asa consequence the wire 19 is'connected through a back contact of the relay through extension wirel 24 to the branch 25 connected tothe A battery marked A? in Fig. 2a. The wire 18c similarly passes through a back contact of the relay to the extension .wire 26 leading to test or listening relay LfS` and ground. 18C-, it will be remembered, leads to the tip or ground side of 'the line, therefore it is the side which in the broadcasting can be made use of with a permanent ground or grounds, without disturbing the balance of the telephone circuit.

The broadcast receiver' at the substation A is shown as comprising an input connection 28 (from the electric light network 200,) a tuned coupler 29, detector tube 30, audio amplifier tubes 3l and 32, andthe usual transformers, 34, 35, the last mentioned transmitting thex amplified audioiwaves to the telephone receiver or loud vspeaker 36.

The filament battery is A2. The plate battery is B2 and suitable timing condensers and coils, tickler coilfor regenerative effects, etc., are provided as required. I should parture from the invention.

remark in passing that this representation of the radio receiver is intended to be typical only. The present invention does 'not concern itself specifically with the design of the local ybroadcast receiver sets, and other' f vcircuits and apparatus may be substituted for those shown in the diagrams without de- The relay L has four pairs of contacts, one pair 27 closing the .wires 25 and 37 trom battery A2 tothe filaments. The Sec` ond pair 27' closes the wires 25 and 38 so as to put battery A2 on the transmitter T', and through the induction coil winding T, to ground. The third and fourth pairs of contacts 27e, 27d, close the wires 39 and 40, form- `thereover from ing terminals of the secondary -induction coil station. -In addition to the hook, the subscriber has a manual switch la by which he can connect the battery wire 42 through a wire 44 to his transmitter T', coil and ground, sofas to energize his talking circuit. l provide an ordinary telephone receiver in series with the seconda-ry of the `induction coil I', and I interpose a pair of condensers g3, g4 between the secondary of the induction coil I .and the telephone receiver on the one hand, and the terminals of relay L5 on the other, so that while the subscriber by means of switch It can connect his telephone T-t for receiving calls over the telephone line, he cannot originate calls the broadcast recelver exe tension. v

Returning now to the central st ation.'and nparticularly to the broadcast department thcreotshown' i'n Fig. 2, T represents a Squier broadcasting transmitter, symbolized in a very simple form, but supposed to contain the usual elements and connected on the output side with `the electric light or power` network 200. This connection in-v cludes suitable devices, known in the art, to exclude high voltage and low frequency currents, surges, hum', etc. Suitable switches are assumed located at a convenient point. The jack J4 connected to the amplifier 252 and thence to the transmitter T, symbolizes a group of 'such jacks or equivalentconnecting means such as automatic switches, vcontrolled by'dials or keys, for connecting any of the wire lines to said transmitter. De tailed appliances, for receiving radio mossages from primary centers, for the switching, and for the local broadcast transmission, are well known in the ant, and need no specific description in this specification.

.Thecord circuit between plugs Pz and P in Fig. 2f" is the same as the operators cord circuit, in Fig. 2, but the broadcast operator also has special test cords such as thatshown plug P4. Here the keys'K-K are of standin the upper part of the figure connected to ard construction, as in the other cords, and f the test Contact ofthe plug1 P4 is connected through suitable resistance to the supervisory I lamp s2 tothe broadcast lbattery B', in eans such as the commutator go being provlded to give special of the multiple jacks J, J', J2, etc. It will be observed that the constant connection of the sleeve orbattery Wire 24 at the radiophone substation to the bus wire 25 of the battery A2, produces charging of that battery by the constant flow of current -therethrough from the main radio battery B at the central otice. This charging circuit may be traced from battery B- through contact of relay L7. wire 19, 19, 19, contact lof relay L, 24, Al, .and through natural yground back to battery B. The amount of ly transmit from one-halflampere to two ory three ampercs, acc'ordingto the line resistance and the voltage of the battery employed.

Vilhcre this Voltage is standard manual telephone voltage, say 22,'and the single Wire resistance to the substation is from 25 to 5() ohms, it Would be possible to maintain the battery ft2 continuously charged, provided the time of discharge be .not too long cxtended, and thecharging be not interrupted by other contingencies. such as the excessive in the art. will bethe best practice. also possible with instruments now well telephone use of the line.

It wish to point out in connection with this, that the art has progressed to a point where lament current required is so small that it -is weli Within the limits of the amperage permissible over the smallest telephone Wires, even continuously flowing, and

therefore direct iced of the lilamcnts over the telephone Wires is not only possible but` for reasons that will be plain to those skilled It is known to supply filament current from electric lighting circuits. and both these methods of feed are Within the scope of the present invention, owing to my combination or' these wires into one system.

For metering the subscribers radio service at the central station, an impulse meter" which may be of the standard type as indicated diagrainmatically at 50 (Fig. 2) or any known orcthe' suitable type capable.

of recording currents-impulses or circuit closures is employed. This meter is arranged to have its energizing circuit closed through a normally open contact '51 of a relay 52 actuated conjointly with the line lamp L', which in the present case is the usual night alarm relay. Foractuating the meter 50 from the subscribcrs broadcast receiving station at substantially constant timel intervals, a meter actuator in the form tone test on the 'test thirnbles' side l of battery B.

of an intermittent circuit closer of any known or other suitable type is provided.

In the present arrangement this actuator 53 is shown as an intermittent thermal switch of the type -used as sign ashers. The energizing circiiit'of the actuator 53 including the winding 54 and contact 55 is connected with the electric light circuit 2.00 through a normally open Contact 56 on the broadcast receiving station switch hook H', While the circuit closing contact 57 is connected in shunt of the subscribers telephone-transmitter circuit-switch-liook-contacts, so that upon closure they will effect a closure of the line circuit in the same manner as when the subscriberstelephone receiver is raised except that the closure is momentary or brief and not continuous.

Tluz's when the radio receiver is in use the switch-hook H being in raised osition maintains the contacts 56 closed Whic i maintain closure of the energizing circuit of the actuator 53 which circuit may be traced :from the lower conductorY of the power circuit through conductor 58, winding 54, Contact 55, conductor 59, .Contact 56, conductor 6() back to the upper conductor of the power circuit. Thiscauses the actuator 53 to Warp back andv forth and intermittently open and close its own circuit in a manner well understood-Which causes the contact 57 tobe inf ternjiittentlyactuated to momentarily close the line circuit at the subscribers end over the following path: Contact 57, conductor 61, switch-hook contact a, line Wire 18, line icoA Wire 19, switch-hook 7L, conductor 62, back to contact 57. Each momentary closure of the subscribers line circuit eti'ects an actuation ot the line relay 4L in the usual manner as when calling, except that the actuation lis 1nomentary,'which in turn effects an actuation of the meter 50 vthrough relay 52 and its Contact 51. The circuit ot relay 52 may be traced from battery B, through Winding of relay 52, line lamp and contact ot line relay L back to the grounded side .of battery B. The circuit of meter 5() may be traced from the free 4or u Y per side of battery B through contact 51 o relay 52, Winding of meter 50 and back by Way of ground'to 'the grounded The meter() as shown is a standard Western Electric line meter'o,

a type' in common use. It has a'high resist-' T his could be replaced by any suitable ma netically actuated would respond to closurefof its circuit at counting device whim.k

v lar Wave length would be the contact 51 of relay 52. Thus, as long as the broadcast receiving station is in use, the meter 50 is actuated at substantially constant recurring periods proportionate in number' to the time the receiving station is in use; meter will be actuated once each time the subscriber cioses his line circuit in initiating a telephone call. and that it will not continue to record the time of use of the radio receiver during use of the telephone substation, there will however be no unfairness in the broadcast service charge'due to the fact that, in` practice, the suspensionjof metering during use of the telephone substation will substantially compensate for the extra actuation of the meter at the initiation of a call.

closer of any suitable type may be used in place of the meter actuator 53, for-example any kind of of fairly constant effect the momcntaryclosurejoi' the telephone line circuit. l l

A number of modificationsl in the system thus specifically described can be made without departure from the scope of the inven tion. For carrier current transmission purposes, as an all metallic circuit is preferable, the telephone circuits, regarded as a network, or any one telephone circuit, may be used as one side of circuit, and the electric lightingl network may be used as the return si In such case, proper arrangements'of condensers or filters at the central broadcasting station and the subscribers stations should 'be employed, in a manner Well understood in the art, to prevent any ground leakage, or any communicationjrom grounds on the electric lighting network to the telephone circuits. As a further modiiication, some wor any of the telephoner circuitsv may be used for outward transmission of the broadcast currents from. central to the subscribers receiving instruments, and another telephone circuit or circuits may be used as the return.

lave access on one side to' the going circuits, and .on the other to the return circuit or circuits, and as transmission on any particucommon as to any particular group of subscribers, inductive effecfs can beneglected.

uch modifications the ordinary electric energy feed (battery) over ordinary telephone circuits is usual, but on the contrary permit Afull use to be made of the following combination, which I believe to be novel: p( 1) energy feed over ordinary telephone circuits as usual, (2), outgoing transmission o f filtered over the telephone clrcuits, `Wave bands over r'common Wave bands (3) return 'of return wires,

It is to be noted that While the paratus t vsaid individual As' stated above, an intermittent circuit.

an electrically operated motor speedvmay be used to a phantom broadcastinge of the circuit..

In such case, the subscribers stations would 1 do notl interfere With..

, stations individually,

1. In a broadcasting system the combina-y tion of a current distributing system comprising va 'connected net work of Wires serving a given area, a communication system composed of separate individual wires, subscribers stations in said area. provided with carrier current receiving apparatus, connections from said subscribers receiving apparatu's to said distributing' system for receiving Waves broadcasted thereon, other connections from said subscribersreceiving apvvires for individu ally receivingand transmittin electrical impulses or Waves thereover, an a central broadcasting statin connected for transmitting to said distributing system of wires, and also having access to said individual wires for communication' dividual subscribers stations.

- 2. In a broadcasting system, a current dis# tributing net work of wires, serving splurality of consumers telephone exchange system having separate wired' circuits leading` to subscribers stations, a plurality of broadcast subscribers stations having broadcast receivers conn'ected to said distributing -net work for commonl service thereoverl and individually connected. to 'telephone circuits for individual communication thereover, and a central broadcasting station with A paratus connected to said distributing Work and having access to said telephone circuits for individual communication with said subscribers stations.

-3. In a broadcasting system, a central broadcasting station equipped with transmitting apparatus, and with ancillary test.- ing, control, metering and supervisory apparatusya plurality of'subscribers stations each having a broadcast receiving set, a common'vvire connection from the central broadcasting transmitter. to all such subscribers vreceiving sets in common and individual broadcasting' station and subscribers sta tlons served therefrom. 1n combination with a wired system adapted to serve a plurality of stations in common, a second independent wired system adapted to serve subscribers receiving apparatus at each subscribers stationl operatively conthereover with the in4 stations in common, ai

nected .with both said wire systems, and

means at the central broadcasting station for transmitting over the irstvvired system to subscribers stations. in 'common and for communicating individually with said subscribers stations over the second Wired system.

5.2{11 a broadcasting system, a central broadcasting station and subscribers stations served thereby in combination with a common wired broadcasting circuit or net Work connecting the central station with the subscribers stations, individua-l Wires connecting said central station with the respective subscribers stations, and a broadcast receiving set at each subscribers station electrically connected on one side to said Wired broadcasting circuit and on the other 'side to its individual Wire circuit for joint operation tbereby. p

broadcasting system, a central broadcasting station and sul'iscribers stations served therefrom. in combination With a Wired power distributing net Work and a wired telephone exchange system, with a broadcast receiving set at each subscribers station affording communication between said central station and the subscribers stations over said net work in common, and over said -telephone system individually, said sets being irresponsivc to ordinary currents carried 'on said net work and said wires respectively.,

l'. In a broadcasting system, a central broadcasting station and subscribers stations served therefrom, in combination With a wired power distributing net Work and a wired telephone exchange system, with uni# tary means at each subscribers station aording communication between said central station and the subscribers stations 'over said net Work in common, and over said telephone system individually, and other means to prevent interference between the currents or Waves thus employed in broadcasting and communicating between1 the centrai station and the subscribers stations, and other currents or Waves normally employed over the said net. Work and the said telephone s stem respectively.

8. 'lin a broadcasting system, 'the combination ont Wired electric light net Work and r. telephone exchange system, with a broadcasting central station and subscribers stations having combined broadcast receiving and teiepbone setslserved by `said central'station, said central station and subscribers" se s beine` interconnected through botlasaid net 'worn and said telephone'system. 9.. lin a, broadcasting system, primary transmitting centers, regional. relaying and distributing centers, a plurality of receiving stations. associated iwith each regional center, common wire connections therefrornto sad regional centers, and separate individual Wire connections therefrom to said regional centers, and unitary means at each receiving station operatively connected with atrasos both said common and said individuatwire connections for communication from and to its regional center.v

10. In a broadcasting system, a current distributing net Work, of wires, serving a plurality ot consumers stations in common, a telephone exchange system havipg individual Wired circuits leading to subscribers statins, a plurality of broadcast. subscribeis stations each having a combined broadcast receiver and telephone set connected on one side to said distributing net Work, and on the other side to its individual telephone circuit, and a central broadcasting station having 'carrier current transmitting apparatus and telephonie transmitting and 'receiving apparatus, said carrier current transnntting apparatus connected to said distributing net Work for broadcasting thereover and said telephone apparatus connected to said telephone circuits for complete metallic circuit communication'with said subscril'iers stations,

ll. ln al broadcasting system, a central broadcasting station equipped with carrier current transmitting apparatus, and with ancillary electric current supply apparatus, a plurality of subscribers stations equipped with receiving apparatus served from said central station, a common Wire connection from the centraLbroadcasting transmitter to all such subscribers stations, individual wire connections from the ancillary apparatus at the central station to the subscribers stations, and means operatively connecting said receiving apparatus with said individual line whereby signals sent from said transmitting apparatus over said common wires may be sent back over said individual Wires.

12. l'n. a broadcasting system, a central broadcasting station equipped 'with carrier current transmitting apparatus, and with ancillary electric current supply apparatus, a plurality of subscribers stations equipped with receiving apparatus served from said central station, a complete signal transmis sion wire connection from the central broadcastingtransmitter to all such subscribers stations in common, individual complete signal transmitting wire connections from the ancillary apparatus at thevcentral station to each ot the subscribers stations, and means wherebyv said transmitting apparatus may be caused to transmit signals out over vsaid common Wire connection and back over any of said individual Wire connections and other means ,at the subscribers stations to taire electric current energy over said indi'- vidual Wires for the operation of said re* ceiving apparatus, y y

13. In a broadcasting system, aicentrai' broadcasting st-ation and subscribersvsta.- tions having broadcast receivers served therefrom, infcombination within wired sysi a Wired :atrasos tem adapted to serve a plurality of said stations in common, and a second independent Wired system adapted to serve subscribers stations rover individual Wire` connections, said broadcast receivers' having their input and output ends connected respectively to the common Wire connection and their respective individual wire connections and means at the central broadcasting station for transmitting signals to subscribers stations over one ofsaid wired systems and for receiving signals from said subscribers stations over the second Wired system.

14. In a broadcasting system, a central broadcasting station and subscribers stations served therefrom, in combination with power distributing net Work and wired telephone exchange system, with 1 means affording commumcation between said central station and the subscribers stations over said net work and over said telephone system as independent signaling channels in seriesg said means beingirresponsive to ordinary currents. carried on said net Work-and said Wires respectively.

15. In a broadcasting system, a central broadcasting station and a plurality of subscribers stations ,having broadcast receivers, all metallic wired circuits extending between said subscribers stations and said central station, and a carrier current transmitting apparatus at said central station, with means to connect the same and the subscribers receivers to a metallic circuit as one `side of Va phantom broadcasting circuit, and to another metalic circuit as the other side or ret`urn Wire thereof.

16. A carrier current distribution system comprising a central station and a plurality of subscribers stations, a plurality of Wired circuits connected to said central station, carrier current transmitting apparatus at said central station, carrier current receiving apparatus at said subscribers stations, means for supplyin electric energy feed to the'subscribers stations over said circuitf means4 for transmitting modulated circuits to said subscribers stations, and means to return said carrier currents over other of said circuits to said transmitting apparatus.

In testimony whereof I hereunto ax my signature. n

EDWARD E. CLEMENT.

carrier currents over some of said 

